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The 2H‐tetrahydro‐4,6‐dioxo‐1,2‐oxazine (TDO) ring, a rare structural motif embedded in the molecular architecture of alchivemycins, is synthesized from 2,2,6‐trimethyl‐4H‐1,3‐dioxin‐4‐one via two routes. Both routes involve the intramolecular trapping of an acylketene intermediate by an internal hydroxy group to form the TDO ring as a key step. The first synthesis was achieved in 29 % overall yield from the starting material by a four‐step sequence featuring a DMAP−CaCl2‐mediated O‐ to C‐acyl migration reaction to install an acyl group at the C5 position of the TDO ring. The second synthesis was completed in 8 % overall yield from the same starting material as the first one through five steps by exploiting a photo‐induced double bromination reaction. [ABSTRACT FROM AUTHOR]

Herein, a three component Catellani‐type reaction catalyzed by the Palladium/Norbornene/CuI (Pd/NBE/CuI) cooperative system by using N‐acylph‐thalimides as acyl electrophiles is reported, which gives access to a series of aromatic ketones. The transformation is performable in the presence of water, albeit with decreased reaction yield. The additive CuI was crucial to facilitate the cleavage of C(O)−N bond of imide. This protocol showed broad substrate scope: both alkyl and aryl acyl groups could be installed at the ortho‐position of aryl iodides; alkenes and boronic acids can be used as termination reagents. [ABSTRACT FROM AUTHOR]

Reactions in solids are of contemporary interest due to applications in pharmaceutical industries to environmental sustainability. Although several reactive crystals that support chemical reactions have been identified and characterized, the same cannot be said about reactive cocrystals. Earlier we correlated the facile acyl group transfer reactions in crystals with supramolecular parameters obtained from the crystal structures. The structure‐reactivity correlation revealed the requirement of proper juxtaposition of electrophile (C=O) and the nucleophile (OH) with distance (∼3.2 Å) and angle (∼90°) along the chain structure. The current article describes the preparation of cocrystals that are capable of supporting intermolecular acyl group transfer reactions in a group of structurally similar molecules. The cocrystals of naphthalene 2,3‐diol and its corresponding diesters showed a facile solid state acyl transfer reaction, which has been well correlated with their crystal structures. [ABSTRACT FROM AUTHOR]

Abstract: A facile and efficient oxidative C−H acylation of N‐substituted pyrazolones using α‐oxocarboxylic acids as an acyl group source was developed. A combination of Cu(OAc)2 and K2S2O8 enables the reaction to proceed smoothly under air and provides a wide array of 4‐acylpyrazolone products in moderate to excellent yields. The mechanism of this transformation is believed to proceed via a copper‐induced decarboxylation to form the acyl‐copper species. This method provides a convenient and useful route for a direct installation of an acyl moiety into bioactive pyrazolone derivatives, which can be further utilized in many applications. [ABSTRACT FROM AUTHOR]

The synthesis of both regioisomers of monoacylated diols has been achieved in one simple step using a Passerini reaction. We examined various substrates and reaction conditions, and the results show that the regioselectivity of the reaction is governed by a choice between five‐ and six‐membered‐ring transition states, and by different rates of acyl migration under different reaction conditions. [ABSTRACT FROM AUTHOR]

Abstract: We describe a selective and mild chemical approach for controlling RNA hybridization, folding, and enzyme interactions. Reaction of RNAs in aqueous buffer with an azide‐substituted acylating agent (100–200 m m) yields several 2′‐OH acylations per RNA strand in as little as 10 min. This poly‐acylated (“cloaked”) RNA is strongly blocked from hybridization with complementary nucleic acids, from cleavage by RNA‐processing enzymes, and from folding into active aptamer structures. Importantly, treatment with a water‐soluble phosphine triggers a Staudinger reduction of the azide groups, resulting in spontaneous loss of acyl groups (“uncloaking”). This fully restores RNA folding and biochemical activity. [ABSTRACT FROM AUTHOR]

An unprecedented palladium(II)-catalyzed biomimetic aliphatic acyl (-COR) group transfer was observed from acyl-α-peroxycoumarins to the ortho CH sites of directing arenes. Here, the CH activation is associated with a concomitant acyl group transfer via a Pd(II)-catalyzed, redox-neutral process. While methods for ortho aroylation (-COAr) are well documented ortho acylation (-COR) processes are scarce, hence the present redox-neutral method is most ideal for o-acylation of directing substrates. [ABSTRACT FROM AUTHOR]

A detailed computational and kinetic analysis of the acetylation of 1-phenylethanol with acetic anhydride catalyzed by planar chiral 4-(dimethylamino)pyridine (DMAP) catalyst (−)- 1 is presented. The study includes a computational investigation of the potential-energy surface including the acylation and stereoselective transition states at the DFT level of theory. Experimentally, the kinetic study shows that the reaction proceeds in a first-order manner in catalyst, whereas both substrates, acetic anhydride and 1-phenylethanol, show fractional order, which is in accordance with steady-state conditions. The fractional order depends on an equilibrium between the free catalyst and the acetylated catalyst. [ABSTRACT FROM AUTHOR]

α,β-Unsaturated acyl cyanides are key bis-electrophile substrates for successful domino enantioselective organocatalyzed Michael-intramolecular acylation domino sequences. This new reactivity has been applied to the synthesis of enantioenriched azaspiro[4,5]decanone ring systems by a formal [3+3]spiroannulation, constituting a rare example of synthesis of glutarimides in an optically active form. [ABSTRACT FROM AUTHOR]

Cover Feature: 2-Sulfanylhydroquinone Dimer as a Switchable Fluorescent Dye (Chem. Eur. J. 62/2019) The monomesylated 2-sulfanyhydroquinone dimer emits blue light upon irradiation with UV light, whereas its photoluminescence activity turns off upon acylation of the phenolic hydroxyl group. 2-sulfanylhydroquinone dimer, acylation, biaryls, fluorescence, hydrolysis. [Extracted from the article]